[MrForbes]

You might want to consider a hinged mechanism also....and if it has pneumatic actuation it will be kind of "springy" and might not need to be retracted to go under the overpass. also think about using a flexible part to knock the ball off.

We don't have any solid part of our robot extending past about 75" height, ever. We discovered that it really is not very difficult to knock the ball off. And catching it is the fun part....